The tetrasubstituted ethylene, bifluorenylidene, reacts very rapidly (4.06 X 10−2 1 mol−1 sec−1 at 0°C) with HCo(CO)4 to give bifluorenyl. α-Phenylacrylonitrile (atroponitrile) reacts even more rapidly under the same conditions (6.0 l mol−sec−1). Other highly substituted ethylenes react very slowly with HCo(CO)4, indicating considerable steric effects. The data are consistent with radical type intermediates
四取代的
乙烯,联
芴基,与HCo(CO)4非常迅速地反应(0°C时为4.06 X 10 -2 1 mol -1 sec -1),得到联
芴基。在相同的条件下(6.0 l mol - sec -1),α-苯基
丙烯腈(a腈)的反应甚至更快。其他高度取代的
乙烯与HCo(CO)4的反应非常缓慢,表明存在很大的空间效应。数据与自由基型中间体一致。